Abuja - Nigerian authorities on Tuesday defused three improvised bombs planted in the main university in Kano, a northern city plagued by an Islamist insurgency.

Police spokesperson Magaji Majia said the bombs had been planted in the faculties of science and law and in the sports complex, but were spotted. Police removed and destroyed them in controlled explosions, he said.

The authorities did not say who was suspected of planting the bombs. Many recent gun and bomb attacks have been claimed by the Islamist militants of Boko Haram, who have have killed hundreds since launching their uprising more than two years ago.

In a video posted on the Internet last week, Boko Haram threatened to attack the media and universities.

Nigeria's second biggest city, Kano has become a focal point for Boko Haram, as it seeks to extend its insurgency outwards.

“Some IEDs (improvised explosive devices) were planted in the university and we have removed them... No life was lost, but it caused a lot of fear and apprehension,” said Kano army spokesperson Ikedichi Iweha.

Gunmen attacked a lecture theatre at the university which was being used for Christian Sunday services on April 29, killing 15 people.

Boko Haram says it is fighting to reinstate a 19th century Islamic empire in Africa's most populous nation, whose 160-million people are split evenly between Muslims and Christians. - Reuters